So, the Deniers' favorite baseless "alternative" for mass extermination at Aktion Reinhard was to take the Nazis' cover language of "Resettlement" at face value. The Jews weren't killed, but actually exiled to some far off regions in the "Russian East".

To see what such a "Resettlement" plan would and should look like, we have the example of the USSR's so called Dekulakuzation in the early 30s. It's a good case study since the expected level of effort should be the same for the Real Resettlement (About 1-2 Million People were "Dekulakized) and the Nonexistent resettlement (1.2 Million Jews were killed at Aktion Reinhard) and the alleged intent of the Nazis was the same as that of the Soviets. Let's compare the Deniers' fantasy resettlement with what a real resettlement program should look like.

Dekulakuzation was meticulously planned and executed. Every step of the process was documented, though the end result was less than ideal since the receiving areas were ill equipped to receive the deportees. In this meticulously planned government program, all of the details were worked out. The Politburo, the OGPU and the Special Committee headed by Andreyev started by deciding and naming the specific areas that so called Kulaks were to be exiled to; Kazakhstan, the Urals, and West Siberia. Budgets were also prepared, and specifically mentioned as being taken from the OGPU's budget. Even as they were "punishing" them, the USSR figured that the "Kulaks" were still valuable sources of productive labor and decided to put them to good use. They specifically listed and quantified the supplies the "Kulaks" would need in their places of exile: food, supplies, clothes, etc. Some records even mention that the Kulaks brought along plows and even horses so that they could continue their farming and cultivate the lands they were exiled to.

Naturally, the large scale movement of this much people (between 1 and 2 million) wasn't easy, and the fallout was huge. The above mentioned target areas all acknowledged the arrival and settlement of the Kulaks, as well as the problems that ensued when large amounts of people suddenly ended up in ill prepared areas. Soviet reports talk about unrest, banditry, and in some cases even Cannibalism that occurred, because the "Kulaks" were at the places they were supposed to be, and the USSR kept a close eye on them all throughout their "sentence". The Soviets even went as far as to keep track of orphans in the places of exile, so they could put them in orphanages and make them into good Soviet Citizens. This is what a Resettlement program looks like.

As Roberto likes to point out, none of these necessary details are available for Aktion Reinhard. No specific locations were mentioned as destinations for the allegedly "resettled" Jews, just the ridiculously vague "Russian East" that wasn't even within Nazi territory. Treblinka and the other 2 Reinhard camps are listed as the Final destinations in Nazi files, unlike the Soviet records that specifically name Kazakhstan, Urals, or West Siberia as the Final Destination. Instead of detailed and quantified lists of the supplies allocated to the deportees and that which they would need, we have detailed and quantified lists of the belongings the Nazis stole from their Jewish victims, because they knew full well that the victims wouldn't need them. And as it should be pointed out, instead of detailed reports or complaints from the alleged receiving areas about the problems or even ordinary actions of the deportees - which we have in abundance for dekulakuzation - there's literally nothing. Even if you think that the Nazis "only" wanted to "resettle" the Jews, they would still be interested in horror stories about what their destitute victims would be doing in exile, that would make great propaganda. Instead, there's nothing.

Conclusion.
The case of Dekulakuzation is a useful example/case study as to what an alleged "Resettlement" program on the scale of what the deniers are implying would look like. The example of Dekulakuzation shows us what we should expect from a "resettlement" program of a similar scale carried out by the Nazis. Nothing about the alleged "resettlement" of Aktion Reinhard looks even remotely similar to this case study, therefore there was no resettlement, and the Vague "Russian East", unlike the well documented exiles to Kazakhstan, Urals, etc, was nothing but a cover story for mass murder.

The Soviets always ran circles around their Nazi counterparts in this are.

It helped that there were actually large areas to send the Kulaks (and others).

My problem with this idea of “Jewish resettlement” is twofold:
1) Lack of pacified areas to send them to. The Germans fought not only the Red Army but partisans in the areas they occupied. These “settlers” were a security risk that no army would tolerate behind their lines and astride their supply lines. The only place to send them would be areas far enough behind the front lines and that was really Poland and the Baltics where these people came from.
2) Lack of anything resembling proof. There are no memos coordinating this alleged movement with the military, no assigned personnel, no witness testimony, etc. We do know there were ghettos in the USSR for local Jews but those were closed and their inhabitants murdered.

No denier I’ve ever dealt with had any answers.

“I noticed this morning that a group of our Landsberg friends have been given their freedom this morning. These include...Schubert, Jost and Nosske. Schubert confessed to...supervising the execution of about 800 Jews...(referring to the order to clean up Simferopol)...Schubert managed to kill all the Jews (by Christmas 1941). Nosske was the one the other defendants called the biggest bloodhound....
Noel, Noel, what the hell.”
Benjamin Ferencz in a letter to Telford Taylor, December 1951